In most imaging setups, the resolution is determined by the numerical aperture of the employed objective lens and the associated optical aberrations. Artificially increasing the space-bandwidth product (SBP) of an imaging system by mechanical means is suboptimal, as it requires precise control over actuation, optical alignment and motion tracking. Furthermore, a mechanical solution simply accepts the intrinsic resolution limit of a conventional microscope's optics, neglecting the computationally addressable problem of resolution enhancement. Lensless microscopy methods such as digital in-line holography and contact-imaging microscopy offer unique imaging capabilities, but also present certain drawbacks. For example, digital in-line holography does not work well for contiguous samples, and contact-imaging microscopy requires a sample to be in close proximity to the sensor.
The current disclosure provides methods and systems that are capable of recovering sample images that bypass the resolution limit of the employed objective lens and correct for the associated optical aberrations. The basic idea of the disclosed methods and systems is to acquire multiple images of the sample by projecting different illumination patterns onto the sample, or by scanning an aperture at the pupil plane of the imaging system. The acquired images will then be digitally processed to recover the high-resolution information beyond the resolution limit of the employed optics, to recover spectral information of the sample, and/or to correct for aberrations of the employed optics.